In the "Copyright HowTo" section of its website, Project Gutenberg explains how to confirm the public domain status of books according to U.S. copyright laws. Here is a summary: (a) Works published before 1923 entered the public domain no later than 75 years from the copyright date: all these works belong to public domain; (b) Works published between 1923 and 1977 retain copyright for 95 years: no such works will enter the public domain until 2019; (c) Works created from 1978 on enter the public domain 70 years after the death of the author if the author is a natural person: nothing will enter the public domain until 2049; (d) Works created from 1978 on enter the public domain 95 years after publication or 120 years after creation if the author is a corporate one: nothing will enter the public domain until 2074. Each copyright legislation is more restrictive than the previous one. A major blow for digital libraries was the amendment to the 1976 Copyright Act signed on October 27, 1998. As explained by Michael Hart in July 1999: "Nothing will expire for another 20 years. We used to have to wait 75 years. Now it is 95 years. And it was 28 years (+ a possible 28-year extension, only on request) before that, and 14 years (+ a possible 14-year extension) before that. So, as you can see, this is a serious degrading of the public domain, as a matter of continuing policy." John Mark Ockerbloom, founder of The Online Books Page in 1993, got also deeply concerned by the 1998 amendment. He wrote in August 1999: "I think it is important for people on the web to understand that copyright is a social contract that is designed for the public good - where the public includes both authors and readers. This means that authors should have the right to exclusive use of their creative works for limited times, as is expressed in current copyright law. But it also means that their readers have the right to copy and reuse the work at will once copyright expires. In the U.S. now, there are various efforts to take rights away from readers, by restricting fair use, lengthening copyright terms (even with some proposals to make them perpetual) and extending intellectual property to cover facts separate from creative works (such as found in the 'database copyright' proposals). There are even proposals to effectively replace copyright law altogether with potentially much more onerous contract law. (...) Stakeholders in this debate have to face reality, and recognize that both producers and consumers of works have legitimate interests in their use. If intellectual property is then negotiated by a balance of principles, rather than as the power play it is too often ends up being ('big money vs. rogue pirates'), we may be able to come up with some reasonable accommodations."